bsps/arm: Add files to Doxygen group

bsps/arm/shared/start/arm-a9mpcore-smp.c

@@ -1,5 +1,13 @@
 /* SPDX-License-Identifier: BSD-2-Clause */
 
+/**
+ * @file
+ *
+ * @ingroup RTEMSBSPsARMShared
+ *
+ * @brief This source file contains the SMP support some Arm devices.
+ */
+
 /*
  * Copyright (C) 2013, 2018 embedded brains GmbH & Co. KG
  *

bsps/arm/xilinx-zynq/start/bspsmp.c

@@ -1,6 +1,15 @@
-/*
- * SPDX-License-Identifier: BSD-2-Clause
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
  *
+ * @ingroup RTEMSBSPsARMZynq
+ *
+ * @brief This source file contains the implementation of
+ *   _CPU_SMP_Start_processor() for Xilinx Zynq 7000 devices.
+ */
+
+/*
  * Copyright (C) 2014 embedded brains GmbH & Co. KG
  *
  * Redistribution and use in source and binary forms, with or without